Driving-wheel for machines moving over soft ground



J. G. SCHULZ.

DRIVING WHEEL FOR MACHINES MOVING OVER SOFT GROUND.

APPLICATION FILED JULY 30; I920.

1 ,386,28 1 Patented Aug- 2, 1921.

3 SHEETSSHEET I.

g w M, M7 (Z44 I. G. SCHULZ.

DRIVING WHEEL FOR MACHINES MOVING OVER SOFT GROUND.

APPLICATION FILED .IULY 30,1920.

Patented Aug. 2, 1921.

3 SHEETS-SHEET 2.

J. G. SCHULZ.

DRIVJNG WHEEL FOR MACHINES MOVING OVER SOFT GROUND.

APPLICATION FILED JULY 30; 1920.

Patented Aug. 2, 1921.

3 SHEETS-SHEET 3- UNITED STATES PATENT OFFICE.

JACQUES GUSTAVE SGHULZ, OF PAR-IS, FRANCE.

DRIVING-WHEEL FOR MACHINES MOVING OVER SOFT GROUND.

Application filed July 30,

To all whom it may concern:

Be it known that I, JACQUES GUs'rAvn SCHULZ, citizen of the Republic of France, residing at Paris, France, have invented certain new and useful Improvements in Driving-\Vheels for Machines Moving Over Soft Ground, of which the following is a specification.

The mechanical propulsion of machines, known at the present time, over arable soils or other soft ground is obtained by means of driving wheels furnished on the periphery of the rim with spikes which penetrate into and grip the soil and thus preventslipping, or by means of caterpillars, winches or tractors. The three last methods have been devised to remedy the following disadvantage of the driving wheels furnished with spikes, for with the latter as soon as the soil is a little greasy, a clot of earth forms between the projections totally or partially masking them, which prevents suflicient penetration of the spikes into the soil and the wheel slips.

The object of the present invention is to clean the hollow spaces between the spikes and thus allow the practical provision of a driving wheel provided with spikes on the periphery thereof free from the disad- .vantage above mentioned.

A construction embodying my invention is illustrated by way of example on the accompanying drawings, in which 2- Figure 1 shows above the axle designated by the broken line 0-0 a transverse vertical section of the contrivance, and beneaththis axle an edge view of the driving wheel.

Fig. 2 is a side elevation of the contrivance and driving wheel.

Fig. 3 is an elevation of the wheel and its cleaner mounted on a vehicle.

A shaft designated in. Fig. l by the broken line 0 0 outside the driving wheel a and parallel to the axle 0 of this wheel, carries scrapers 7).

These scrapers are intended to remove the soil which accumulates in the spaces between the spikes of the wheel a.

The holder mounted on the rotatable shaft 0 0 has a plurality of arms, each arm' carrying a number of scrapers, e. 9. three. Each scraper consists of a steel-blade. The extremity of each steel blade is beveled; the

' edge thus formed is parallel to the shaft 0 and scrapes off the earth lodged in the spaces between the spikes of the wheel a.

The distance separating the two axes of Specification of Letters Patent. Patented Aug. 2, 1921.

1920. Serial No. 400 .i7e.

lVhile the wheel a turns around its axle 0-0, the tool-holder turns in the opposite direction with its shaft 0 These two motions are interdependent and the ratio of their speeds is determined by the requirement that at each revolution of the wheel a one scraper, and only one, passes into each of the spaces between the spikes of this wheel. If therefore the latter, has an angular velocity 0, and N spikes and the shaft 0 0 at scrapers, the angular velocity m of this shaft 0 must be i Moreover the scrapers must pass into each of the spaces between the spikes of the wheel a and also be there displaced in such a manner that theirv edge, in passing as closely as possible to the sides of these spikes and the part of the rim separating them, will clear away the accumulated soil from these surfaces.

This result is obtained by employing with the set of scrapers previously described, spikes of such a shape that the profile of the hollow which unites their edges with each other may fulfil this condition.

This profile 0 will be obtained by a geometric construction analogous to that for c Care must be taken in fixing 00 N and n,

to select them in such a way that, conversely to what happens with gearing where an endeavor is made to reduce friction to a minimum, the part utilized of the profile 0 will not be astride the pitch circle of the wheel, but, on the contrary, situated distinctly outside this circle, in order to obtain a continual gliding of the scraper on the surfaces of the hollow separating the spikes and thus obtain an effective scraping action.

The number of spikes of a wheel being previously fixed, their theoretical height is determined by the intersections d of the successive profiles 0, obtained as previously stated, the said intersections giving the theoretical situation ofthe edges of the spikes.

In the example given on the accompany- .ing drawings of an embodiment of the invention, n=2 and N=16 have been selected.

The profile 0, obtained as previously explained, gives the general form of the hollow separating the edges of two consecutive spikes.

, In practice it is replaced by the profile e f g it. Of this profile, f g is a portion of the wheel rim and g h are the opposing sides of two consecutive spikes. This profile e 7 g it should be entirely, somewhat outside the theoretical profile. c, to allow the scrapers b to work in the spaces between the spikes of the wheel, without their edges, owing to play of themechanism, coming into contact with the sides. Infact it is not necessary to have friction between the edges and the sides to obtain a satisfactory removal of the soil. It is sufficient if the edge just clears the sides.

The driving wheel and the tool holder, the

movements of whichmust be interdependent are, in the example given, connected with one another by the following driving connection:--

An internal spur wheel 2' is secured to the driving wheel. It drives a toothed pinion 70, carried by one extremity of an intermediate shaft Z the other end of which carries a spur wheel m, which in turn drives a spur pinion n. This latter is fast with the tool holder and is mounted on the shaft 0 -0 .v

In the firstplace, it is seen that by the preceding, driving connection, the motions of the driving wheel and tool holder are inverse. Moreover considering that in the example given n::2 and N:16 the relation between w and w must be p Thus for each of the two pairs of spur gearing previously described, the following ratios have been taken :4 for the first pair (that which has an internal spur wheel) and 2 for the second. Thus 2 4z8 is obtained.

Moreover to facilitate machining of the rim of the driving wheel and enable at the same time, the interchangeability of the spikes and their construction in a metal harder than the remainder of the wheel,

these spikes are not formed on the wheel itself, but are applied and connected to this wheel by dove tail joints.

On the other hand to obtain a better grip of the wheel on the soil,each spike is not continuous nor equal in length to the thickness of the driving wheel, but is formed by a row of teeth 12, three'in number. In the example given on. the accompanying drawings these teeth are interchangeable and placed between the two same generating lines of the driving wheel a; they are separated frorneach other by free spaces Q the dimensions of which are determinedby praca section of reduced resistance, where rupture of the scraper will occur if too great a resistance is encountered, arising for example, from ajstone lodged between a scraper and a spike of the driving wheel;

It may be added that in the case of backward running when, owing to play of the gearing, the scrapers and spikes of the wheel come into contact, it will be suiiicient to mount these scrapers on trippers working only in the reversing direction and allowing the scrapers to give'way to the spikes when they meet.

Claim.

The combination with a spiked driving wheel for machines intended to move over soft ground, o-farotary scraper-wheel adapt-- ed to rotate about an axis of fixed relative position in the frame of the machine, and scrapers carried by the said wheel scraper so as to remove the soil between the projections of the saidv driving wheel, the outerprofile of the said driving wheel being such that ateach rotation of the same,'the scraping edges of the scrapers carried by the said scraper-wheel pass with a slight clearance over the entire surface of each projection, the rotationof the said scraperwheel being in opposite direction to that of the 7 said driving wheel so that upon the rotation ofthe said two wheels the scrapers carried by the said scraper-wheel successively enters the depressions between the projections of the said driving wheel.

In testimony whereof I have afiixed my signature in the presence of two witnesses.

JACQUES GUSTAVE SGHULZ. 

